HARQ/ACK codebook size determination

ABSTRACT

Embodiments of the present disclosure describe devices, methods, computer-readable media and systems configurations for determining a hybrid automatic repeat request (HARQ)-acknowledgment (ACK) codebook in wireless communication networks.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims priority to U.S. Provisional PatentApplication No. 61/612,188, filed Mar. 16, 2012, entitled “WIRELESSCOMMUNICATION SYSTEMS AND METHODS,” the entire disclosure of which ishereby incorporated by reference.

FIELD

Embodiments of the present invention relate generally to the field ofcommunications, and more particularly, to determining size of a hybridautomatic repeat request-acknowledgment (HARQ-ACK) codebook in wirelesscommunication networks.

BACKGROUND

Release 8 of the Third Generation Partnership Project (3GPP) Long-TermEvolution (LTE) standard describes piggybacking uplink controlinformation (UCI) on a physical uplink shared channel (PUSCH). Thechannel quality indicator/pre-coding matrix indicator (CQI/PMI)resources are placed at the beginning of uplink shared channel (UL-SCH)data resources and mapped sequentially to all single-carrier frequencydivision multiple access (SC-FDMA) symbols on one subcarrier beforecontinuing on the next subcarrier. The UL-SCH data is rate-matchedaround the CQI/PMI data. The HARQ-ACK resources are mapped to SC-FDMAsymbols by puncturing the PUSCH data resource elements (REs). Reducingthe PUSCH REs punctured by the HARQ-ACK symbols would, therefore,improve the PUSCH performance.

In light of the above, Release 8 provides a 2-bit downlink assignmentIndex (DAI) in downlink control information (DCI) format 0/4, V_(DAI)^(UL), which is used to indicate total number of downlink (DL)assignments in a bundling window. Assuming the bundling window size isM, only V_(DAI) ^(UL) HARQ-ACK bits, rather than M bits, need to be fedback to a transmitting device, e.g., an enhanced node base station(eNB), if PUSCH transmission is adjusted based on a detected PDCCH withDCI format 0/4. Thus, (M−V_(DAI) ^(UL)) useless HARQ-ACK bits,corresponding to DL subframes that were not scheduled by the eNB, arereduced.

Release 10 of the LTE standard (Rel-10) introduces carrier aggregation,in which more than one component carrier (CC) may be used for datatransmissions. In a Release 10 time division duplexing (TDD) system, theHARQ-ACK codebook size, in case of piggybacking on PUSCH, is determinedby the number of CCs, their configured transmission mode, and number ofdownlink subframes in bundled window. For TDD UL-DL configurations 1-6,and when PUCCH format 3 is configured for transmission of HARQ-ACK, theHARQ-ACK codebook size is determined by:n _(HARQ) =B _(c) ^(DL)(C+C ₂),  (1)

where C is the number of configured CCs, C₂ is the number of CCsconfigured with a multiple-input, multiple-output (MIMO) transmissionmode that enables reception of two transport blocks; B_(c) ^(DL) is thenumber of downlink subframes for which UE needs to feedback HARQ-ACKbits for the c^(th) serving cell. For TDD UL-DL configuration 1, 2, 3,4, and 6, the UEs will assume B_(c) ^(DL) on PUSCH subframe n as:B _(c) ^(DL) =W _(DAI) ^(UL),  (2)

where W_(DAI) ^(UL) is determined by the DAI in DCI format 0/4 accordingto the following table:

TABLE 1 DAI MSB, LSB W_(DAI) ^(UL) 0, 0 1 0, 1 2 1, 0 3 1, 1 4

The DAI may be communicated in a subframe that has a predeterminedassociation with subframe n for each serving cell. For example, the DAImay be communicated in subframe n−k′, where k′ is defined in thefollowing table:

TABLE 2 TDD UL/DL subframe number n Configuration 0 1 2 3 4 5 6 7 8 9 16 4 6 4 2 4 4 3 4 4 4 4 4 4 5 4 6 7 7 5 7 7

Since the TDD UL-DL configuration of each serving cell is alwaysidentical in Rel-10 and W_(DAI) ^(UL) is definitely no larger than thebundling window size, the HARQ-ACK codebook size determined by W_(DAI)^(UL) is always equal to minimum HARQ-ACK bits number and is the besttradeoff between HARQ-ACK overhead and performance.

In Release 11 of the 3GPP LTE standard, interband CA of TDD with CCshaving different UL-DL configurations for each serving cell issupported. Having different UL-DL configurations in the differentserving cells may result in different HARQ-ACK bundling windows.Therefore, the UL grant based HARQ-ACK codebook size determination inprevious releases may not effectively reduce the HARQ-ACK overhead.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will be readily understood by the following detaileddescription in conjunction with the accompanying drawings. To facilitatethis description, like reference numerals designate like structuralelements. Embodiments are illustrated by way of example and not by wayof limitation in the figures of the accompanying drawings.

FIG. 1 schematically illustrates a wireless communication network inaccordance with various embodiments.

FIG. 2 illustrates an example TDD communication structure with HARQ-ACKtiming information in accordance with various embodiments.

FIG. 3 is a flowchart illustrating a method of determining a HARQ-ACKcodebook size that may be performed by a user equipment in accordancewith various embodiments.

FIG. 4 is a HARQ-ACK bits generation table in accordance with someembodiments.

FIG. 5 schematically depicts an example system in accordance withvarious embodiments.

DETAILED DESCRIPTION

Illustrative embodiments of the present disclosure include, but are notlimited to, methods, systems, computer-readable media, and apparatusesfor determining a size of a HARQ-ACK codebook in wireless communicationnetworks. Various embodiments may provide user equipment (UE) thatoperate in conformance with Release 11 of 3GPP LTE (hereinafter“Rel-11”) (and later releases) with the ability to determine HARQ-ACKcodebook size on PUSCH in a manner to reduce HARQ-ACK overhead whilemaintaining HARQ-ACK performance for interband CA of TDD CCs withdifferent UL-DL configurations for different serving cells. In thismanner, described UEs may adaptively determine the desired HARQ-ACKcodebook size to puncture the PUSCH REs that will reduce negative impacton the PUSCH with little to no additional overhead.

Various embodiments may be described with reference to specificconfigurations, e.g., TDD UL-DL configurations and special subframeconfigurations; formats, e.g., DCI formats; modes, e.g., transmissionmodes; etc. These configurations, formats, modes, etc., may be definedconsistent with presently published LTE documents, e.g., Rel-10 and/orRel-11 technical specifications.

Various aspects of the illustrative embodiments will be described usingterms commonly employed by those skilled in the art to convey thesubstance of their work to others skilled in the art. However, it willbe apparent to those skilled in the art that alternate embodiments maybe practiced with only some of the described aspects. For purposes ofexplanation, specific numbers, materials, and configurations are setforth in order to provide a thorough understanding of the illustrativeembodiments. However, it will be apparent to one skilled in the art thatalternate embodiments may be practiced without the specific details. Inother instances, well-known features are omitted or simplified in ordernot to obscure the illustrative embodiments.

Further, various operations will be described as multiple discreteoperations, in turn, in a manner that is most helpful in understandingthe illustrative embodiments; however, the order of description shouldnot be construed as to imply that these operations are necessarily orderdependent. In particular, these operations need not be performed in theorder of presentation.

The phrase “in some embodiments” is used repeatedly. The phrasegenerally does not refer to the same embodiments; however, it may. Theterms “comprising,” “having,” and “including” are synonymous, unless thecontext dictates otherwise. The phrase “A and/or B” means (A), (B), or(A and B). The phrase “A/B” means (A), (B), or (A and B), similar to thephrase “A and/or B”. The phrase “at least one of A, B and C” means (A),(B), (C), (A and B), (A and C), (B and C) or (A, B and C). The phrase“(A) B” means (B) or (A and B), that is, A is optional.

Although specific embodiments have been illustrated and describedherein, it will be appreciated by those of ordinary skill in the artthat a wide variety of alternate and/or equivalent implementations maybe substituted for the specific embodiments shown and described, withoutdeparting from the scope of the embodiments of the present disclosure.This application is intended to cover any adaptations or variations ofthe embodiments discussed herein. Therefore, it is manifestly intendedthat the embodiments of the present disclosure be limited only by theclaims and the equivalents thereof.

As used herein, the term “module” may refer to, be part of, or includean Application Specific Integrated Circuit (ASIC), an electroniccircuit, a processor (shared, dedicated, or group) and/or memory(shared, dedicated, or group), combinational logic circuit, or otherelectronic circuit that provides the described functionality. In variousembodiments, the module may execute instructions stored in one or morecomputer-readable media to provide the described functionality.

FIG. 1 schematically illustrates a wireless communication network 100 inaccordance with various embodiments. Wireless communication network 100(hereinafter “network 100”) may be an access network of a 3GPP LTEnetwork such as evolved universal terrestrial radio access network(E-UTRAN). The network 100 may include a base station, e.g., enhancednode base station (eNB) 104, configured to wirelessly communicate withuser equipment (UE) 108.

As shown in FIG. 1, the UE 108 may include feedback controller 112coupled with transceiver module 116. The transceiver module 116 may befurther coupled with one or more of a plurality of antennas 132 of theUE 108 for communicating wirelessly with other components of the network100, e.g., eNB 104.

In some embodiments, the UE 108 may be capable of utilizing carrieraggregation (CA) in which a number of component carriers (CCs) areaggregated for communication between the eNB 104 and the UE 108. Thetransceiver module 116 may be configured to communicate with the eNB 104via a plurality of serving cells utilizing a respective plurality ofCCs. The CCs may be disposed in different bands and may be associatedwith different TDD UL-DL configurations (hereinafter also referred to as“UL-DL configurations”). Thus, in some embodiments, at least two servingcells may have different UL-DL configurations.

Table 3 below shows example UL-DL configurations that may be employed invarious embodiments of the present invention.

TABLE 3 TDD UL-DL Subframe number configuration 0 1 2 3 4 5 6 7 8 9 0 DS U U U D S U U U 1 D S U U D D S U U D 2 D S U D D D S U D D 3 D S U UU D D D D D 4 D S U U D D D D D D 5 D S U D D D D D D D 6 D S U U U D SU U D

In Table 3, D is a subframe for a downlink transmission, U is a subframefor an uplink transmission, and S is a special subframe used, e.g., fora guard time. In some embodiments, a special subframe may include threefields: downlink pilot time slot (DwPTS), which may include the DCI,guard period (GP), and uplink pilot time slot (UpPTS)

In an initial connection establishment, the UE 108 may connect with aprimary serving cell (PCell) of the eNB 104 utilizing a primary CC,which may also be referred to as CC₀. This connection may be used forvarious functions such as security, mobility, configuration, etc.Subsequently, the UE 108 may connect with one or more secondary servingcells (SCells) of the eNB 104 utilizing one or more secondary CCs. Theseconnections may be used to provide additional radio resources.

FIG. 2 illustrates an example TDD communication structure 200 withHARQ-ACK timing information in accordance with an embodiment. In the TDDcommunication structure 200, three serving cells may be configured forcommunication between the eNB 104 and the UE 108. For example, a PCellhaving UL-DL configuration 0, an SCell 1 having UL-DL configuration 2,and an SCell 2 having UL-DL configuration 1. In other embodiments, othernumber of serving cells may be configured for communication between theeNB 104 and the UE 108.

In the TDD communication structure 200, the PCell may have a bundlingwindow, M₀, that includes one subframe that may include downlinktransmissions, e.g., PDSCH transmissions or PDCCH transmissionsindicating downlink semi-persistent scheduling (SPS) release, for whichcorresponding HARQ-ACK information is to be transmitted as a PUSCHtransmission in an associated uplink subframe, e.g., subframe 7 of theSCell 1. The SCell 1 may have a bundling window, M₁, that includes foursubframes that may include downlink transmissions for whichcorresponding HARQ-ACK information is to be transmitted as a PUSCHtransmission in an associated uplink subframe, e.g., subframe 7 of theSCell 1. The SCell 2 may have a bundling window, M₂, that includes twosubframes that may include downlink transmissions for whichcorresponding HARQ-ACK information is to be transmitted as a PUSCHtransmission in an associated uplink subframe, e.g., subframe 7 of theSCell 1. The association between the DL subframes of the respectivebundling windows and the UL subframe that will be used to transmit thecorresponding HARQ-ACK information may be based on a predetermined HARQtiming reference. An example of such HARQ timing references is shown anddiscussed below with respect to Table 4.

In the example shown in FIG. 2, all of the subframes capable of carryingdownlink transmissions for which corresponding HARQ-ACK information isto be transmitted are shown as having PDSCH transmissions. However, inother embodiments, the eNB may not schedule downlink transmissions onone or more of these subframes.

FIG. 3 illustrates a method 300 of determining a HARQ-ACK codebook sizein accordance with some embodiments. Method 300 may be performed by afeedback controller of a UE, e.g., feedback controller 112 of UE 108. Insome embodiments, the UE may include and/or have access to one or morecomputer-readable media having instructions stored thereon, that, whenexecuted, cause the UE, or feedback controller, to perform the method300.

At 304, the feedback controller may determine the HARQ-ACK timing andbundling window for each configured serving cell. In some embodiments,the feedback controller may determine, for each configured serving cell,a total number of subframes within a bundling window that is associatedwith an uplink subframe. In general, the HARQ-ACK bundling window mayinclude both downlink subframes and special subframes, as both arecapable of carrying PDSCH transmissions. However, in some embodiments,certain special subframes may be excluded from the bundling window inorder to reduce HARQ-ACK codebook size. For example, in specialsubframes of configurations 0 and 5 with normal downlink cyclic prefix(CP) or configurations 0 and 4 with extended downlink CP may be excludedfrom the bundling window as they typically do not carry PDSCHtransmissions. The special subframe configurations may be definedconsistent with Table 4.2-1 of 3GPP Technical Specification (TS) 36.211V 10.5.0 (2012-06).

In some embodiments, the HARQ-ACK timing and bundling windows, M_(c),may be determined according to a predetermined downlink association setindex K: {k₀, k₁, . . . k_(M-1)} for TDD as illustrated in the UL-DLconfigurations for HARQ timing reference of Table 4.

TABLE 4 UL-DL Subframe n Configuration 0 1 2 3 4 5 6 7 8 9 0 — — 6 — 4 —— 6 — 4 1 — — 7, 6 4 — — — 7, 6 4 — 2 — — 8, 7, 4, 6 — — — — 8, 7, 4, 6— — 3 — — 7, 6, 11 6, 5 5, 4 — — — — — 4 — — 12, 8, 7, 11 6, 5, 4, 7 — —— — — — 5 — — 13, 12, 9, 8, 7, 5, 4, 11, 6 — — — — — — — 6 — — 7 7 5 — —7 7 —

In various embodiments, each serving cell may have a HARQ timingreference that is the same or different from the UL-DL configuration ofthe serving cell. The UL-DL configuration of the serving cell iscommunicated in the serving cell's System Information Block (SIB) 1 and,therefore, may also be referred to as the serving cell's SIB 1configuration. The HARQ timing reference of a PCell may be the same asthe PCell's SIB1 configuration, while a HARQ timing reference of anSCell may be selected by considering both the SCell's SIB1 configurationand the PCell's SIB1 configuration according to Table 5.

TABLE 5 UL-DL configuration for HARQ timing SCell SIB1 UL-DLconfiguration reference 0 1 2 3 4 5 6 PCell SIB1 0 0 1 2 3 4 5 6 UL-DL 11 1 2 4 4 5 1 configuration 2 2 2 2 5 5 5 2 3 3 4 5 3 4 5 3 4 4 4 5 4 45 4 5 5 5 5 5 5 5 5 6 6 1 2 3 4 5 6

According to Table 5, and with reference to FIG. 2, the PCell will useUL-DL configuration 0 for its HARQ timing reference, SCell 1 will useUL-DL configuration 2 for its HARQ timing reference, and SCell2 will useUL-DL configuration 1 for its HARQ timing reference. While thisembodiment illustrates both SCells using their SIB1 configurations forHARQ timing reference, an SCell may use other UL-DL configurations forits HARQ timing reference in other embodiments. For example, if SCell 1had a SIB1 configuration of 3 and the PCell had a SIB1 configuration of1, the SCell would use UL-DL configuration 4 for its HARQ timingreference.

To further illustrate use of Tables 4 and 5, consider the following.With subframe 7 (e.g., n=7) of the SCell 1 being designated as theuplink subframe for transmitting HARQ-ACK information, the associateddownlink subframes may be determined by n−k, where kεK. The size of thebundling window, M_(c), is the cardinality of the set K of elements, andthe specific subframes of the bundling window are determined by n−k₀, .. . n−k_(M-1). So, the size of the bundling window of the PCell, M₀, is1 (given that only one element is associated with UL-DL configuration 0,subframe n=7 in Table 4), and the downlink subframe of M₀ is 7−6=1,e.g., DL subframe 1. The size of the bundling window of SCell 1, M₁, is4 (given four elements of Table 4) and the DL subframes of M₁ aresubframe 3 (7-4), subframe 1 (7-6), subframe 0 (7-7), and subframe 9 ofprevious frame (7-8). The size of the bundling window of SCell 2, M₂, is2 (given two elements of Table 4) and the DL subframes of M₂ aresubframe 0 (7-7) and subframe 1 (7-6).

At 308, the feedback controller may determine a DAI. The DAI may becommunicated in a subframe that has a predetermined association with theuplink subframe, n, that will carry the HARQ-ACK information for thebundling windows, e.g., subframe 7 in SCell 1. In some embodiments, theDAI may be communicated in subframe n−k′, where k′ is defined in Table2. In some embodiments, the DAI may be used to determine W_(DAI) ^(UL)according to Table 1. W_(DAI) ^(UL) may correspond to a maximum value ofnumber of scheduled downlink subframes within bundling windows of theplurality of serving cells. With reference to FIG. 2, W_(DAI) ^(UL)=4because 4 downlink subframes are scheduled in SCell 1.

At 312, the feedback controller may determine a number of HARQ-ACK bits,which correspond to the configured serving cells, on a PUSCH of theuplink subframe. In some embodiments, the feedback controller maydetermine the number of HARQ-ACK bits, for each serving cell, based onthe W_(DAI) ^(UL), which is based on the DAI for uplink resourceallocation, and the number of subframes of the bundling window of thecorresponding serving cell according to the HARQ timing referenceconfiguration.

In some embodiments, the number of HARQ-ACK bits for the c^(th) servingcell, O_(c), may be determined by the following equation.

$\begin{matrix}{{O_{c} = {{{Min}\left( {M_{c}^{DL},{W_{DAI}^{UL} + {4\left\lceil \frac{\left( {U - W_{DAI}^{UL}} \right)}{4} \right\rceil}}} \right)}*C_{c}^{DL}}},} & {{Equation}\mspace{14mu} 1}\end{matrix}$

where U is a maximum value of U_(c), among all configured serving cells,U_(c) is the total number of subframes with received transmissions(e.g., PDSCHs and PDCCHs indicating downlink SPS release) in bundlingwindow (e.g., subframe(s) n−k where kεK as described with respect toTable 4) of the c^(th) serving cell, W_(DAI) ^(UL) is determined by theDAI included in DCI, which may have format 0 or 4, that allocates uplinktransmission resource of the serving cell in which the UCI piggybackingon the PUSCH (e.g., SCell 1) according to Table 1 in subframe n−k′,where k′ is defined in Table 2; C_(c) ^(DL)=1 if transmission modeconfigured in the c^(th) serving cell supports one transport block andC_(c) ^(DL)=2 otherwise; and Min(X, Y)=X if X≦Y, and Min(X, Y)=Yotherwise.

In embodiments in which none of the plurality of aggregated servingcells include a configuration 5 as a HARQ timing referenceconfiguration, W_(DAI) ^(UL) will be at least as large as U, therebycanceling out the

$4\left\lceil \frac{\left( {U - W_{DAI}^{UL}} \right)}{4} \right\rceil$term of Equation 1. Thus, Equation 1 is reduced to:O _(c)=Min(M _(c) ^(DL) ,W _(DAI) ^(UL))*C _(c) ^(DL).  Equation 2

Thus, in some embodiments, Equation 2 will be used for HARQ-ACKtransmission in an UL subframe n and on the PUSCH adjusted by itsassociated UL grant with W_(DAI) ^(UL) if none of the HARQ timingreference configurations of the aggregated serving cells isconfiguration 5, and Equation 1 will be used for HARQ-ACK transmissionin an UL subframe n and on the PUSCH adjusted by its associated UL grantwith W_(DAI) ^(UL) if the HARQ timing reference configuration of any ofthe aggregated serving cells is configuration 5.

It may be noted that in some embodiments, neither Equation 1 or 2 may beused in situations in which the serving cell that performs the PUSCHscheduling (e.g., SCell 1 in FIG. 2) has a SIB1 configuration 0. Inthese embodiments, the eNB may not be able to transmit DAI in DCI format0/4 and, therefore, the UE will not be able to determine W.

The HARQ-ACK feedback bits O_(c,0) ^(ACK), O_(c,1) ^(ACK), . . . ,O_(c,o) _(c) ^(ACK) for the c^(th) serving cell are constructed asfollows, where c≧0: the HARQ-ACK for a PDSCH transmission associatedwith a DCI message of a PDDCH or a PDCCH transmission indicatingdownlink SPS release in subframe n−k is associated with O_(c,DAI(k)−1)^(ACK) if transmission mode configured in the c^(th) serving cellsupports one transport block, or associated with O_(c,DAI(k)−2) ^(ACK)and O_(c,DAI(k)−1) ^(ACK) otherwise, where DAI(k) is the value of DAI,for resource allocation of downlink subframe, in DCI format1A/1B/1D/1/2/2A/2B/2C detected in subframe n−k depending on the bundlingwindow in the c^(th) serving cell. The HARQ-ACK feedback bits withoutany detected PDSCH transmission or without detected PDCCH indicatingdownlink SPS release may be set to NACK.

An example is provided below, with reference to FIG. 2 and assumingtransmission mode 4 with two transport blocks enabled is configured. Thespecial subframe configuration of each CC is configuration 3 with normaldownlink cyclic prefix (CP). As stated above, the eNB, in this example,may transmit at each opportunity within the designated bundling windows,e.g., subframe 1 of PCell, subframes 9, 0, 1, and 3 of SCell 1, andsubframes 0 and 1 of SCell 2. Further, the UE may receive, in subframe 3of the SCell 1, the uplink grant for the PUSCH transmission at subframe7 of the SCell 1. Since the maximum value of total number of PDSCHscheduled subframes within the bundling windows is 4 according topresent assumptions, the W, of uplink grant for subframe 7 shall be setas 4 by the eNB. According to Equation 1, the O₀ value of HARQ-ACK bitsfor PCell may be calculated as follows

$O_{0} = {{{{Min}\left( {1,{4 + {4\left\lceil \frac{\left( {4 - 4} \right)}{4} \right\rceil}}} \right)}*2} = 2.}$

In the same manner, the HARQ-ACK bits for SCell 1 and SCell 2 may bedetermined as O₁=8 and O₂=4, respectively. This is shown, graphically,in HARQ-ACK bits generation table 400 of FIG. 4 in accordance with someembodiments. Were the HARQ-ACK bits determined according to the Rel-10methodology, the results would be O₀=8, O₁=8 and O₂=8.

At 316, the feedback controller may determine the HARQ-ACK codebook sizeon the PUSCH of the uplink subframe. The determination of the HARQ-ACKcodebook size may be done by aggregating the number of HARQ-ACK bitsthat corresponds to each of the plurality of serving cells according tothe following equation,

$\begin{matrix}{O = {\sum\limits_{c = 0}^{N_{Cells}^{DL} - 1}{O_{c}.}}} & {{Equation}\mspace{14mu} 2}\end{matrix}$

In the above discussed example, O=14. In the Rel-10 methodology, O=24.Thus, the described embodiments result in a 42% reduction in HARQ-ACKoverhead. In this manner, the PUSCH performance and system throughputmay be improved without impacting HARQ-ACK performance.

The UE 108 described herein may be implemented into a system using anysuitable hardware and/or software to configure as desired. FIG. 5illustrates, for one embodiment, an example system 500 comprising one ormore processor(s) 504, system control logic 508 coupled with at leastone of the processor(s) 504, system memory 512 coupled with systemcontrol logic 508, non-volatile memory (NVM)/storage 516 coupled withsystem control logic 508, a network interface 520 coupled with systemcontrol logic 508, and input/output (I/O) devices 532 coupled withsystem control logic 508.

The processor(s) 504 may include one or more single-core or multi-coreprocessors. The processor(s) 504 may include any combination ofgeneral-purpose processors and dedicated processors (e.g., graphicsprocessors, application processors, baseband processors, etc.).

System control logic 508 for one embodiment may include any suitableinterface controllers to provide for any suitable interface to at leastone of the processor(s) 504 and/or to any suitable device or componentin communication with system control logic 508.

System control logic 508 for one embodiment may include one or morememory controller(s) to provide an interface to system memory 512.System memory 512 may be used to load and store data and/or instructionsfor system 500. In some embodiments, the system memory 512 may includeHARQ logic 524 that, when executed, cause a feedback controller toperform the various operations described herein. System memory 512 forone embodiment may include any suitable volatile memory, such assuitable dynamic random access memory (DRAM), for example.

NVM/storage 516 may include one or more tangible, non-transitorycomputer-readable media used to store data and/or instructions, forexample, HARQ logic 524. NVM/storage 516 may include any suitablenon-volatile memory, such as flash memory, for example, and/or mayinclude any suitable non-volatile storage device(s), such as one or morehard disk drive(s) (HDD(s)), one or more compact disk (CD) drive(s),and/or one or more digital versatile disk (DVD) drive(s), for example.

The NVM/storage 516 may include a storage resource physically part of adevice on which the system 500 is installed or it may be accessible by,but not necessarily a part of, the device. For example, the NVM/storage516 may be accessed over a network via the network interface 520 and/orover Input/Output (I/O) devices 532.

Network interface 520 may have a transceiver module 522, similar totransceiver module 116, to provide a radio interface for system 500 tocommunicate over one or more network(s) and/or with any other suitabledevice. In various embodiments, the transceiver module 522 may beintegrated with other components of system 500. For example, thetransceiver module 522 may include a processor of the processor(s) 504,memory of the system memory 512, and NVM/Storage of NVM/Storage 516.Network interface 520 may include any suitable hardware and/or firmware.Network interface 520 may include a plurality of antennas to provide amultiple input, multiple output radio interface. Network interface 520for one embodiment may include, for example, a wired network adapter, awireless network adapter, a telephone modem, and/or a wireless modem.

For one embodiment, at least one of the processor(s) 504 may be packagedtogether with logic for one or more controller(s) of system controllogic 508. For one embodiment, at least one of the processor(s) 504 maybe packaged together with logic for one or more controllers of systemcontrol logic 508 to form a System in Package (SiP). For one embodiment,at least one of the processor(s) 504 may be integrated on the same diewith logic for one or more controller(s) of system control logic 508.For one embodiment, at least one of the processor(s) 504 may beintegrated on the same die with logic for one or more controller(s) ofsystem control logic 508 to form a System on Chip (SoC).

In various embodiments, the I/O devices 532 may include user interfacesdesigned to enable user interaction with the system 500, peripheralcomponent interfaces designed to enable peripheral component interactionwith the system 500, and/or sensors designed to determine environmentalconditions and/or location information related to the system 500.

In various embodiments, the user interfaces could include, but are notlimited to, a display (e.g., a liquid crystal display, a touch screendisplay, etc.), a speaker, a microphone, one or more cameras (e.g., astill camera and/or a video camera), a flashlight (e.g., a lightemitting diode flash), and a keyboard.

In various embodiments, the peripheral component interfaces may include,but are not limited to, a non-volatile memory port, a universal serialbus (USB) port, an audio jack, and a power supply interface.

In various embodiments, the sensors may include, but are not limited to,a gyro sensor, an accelerometer, a proximity sensor, an ambient lightsensor, and a positioning unit. The positioning unit may also be partof, or interact with, the network interface 520 to communicate withcomponents of a positioning network, e.g., a global positioning system(GPS) satellite.

In various embodiments, the system 500 may be an eNB or a mobilecomputing device such as, but not limited to, a laptop computing device,a tablet computing device, a netbook, a smartphone, etc. In variousembodiments, system 500 may have more or less components, and/ordifferent architectures.

Although certain embodiments have been illustrated and described hereinfor purposes of description, a wide variety of alternate and/orequivalent embodiments or implementations calculated to achieve the samepurposes may be substituted for the embodiments shown and describedwithout departing from the scope of the present disclosure. Thisapplication is intended to cover any adaptations or variations of theembodiments discussed herein. Therefore, it is manifestly intended thatembodiments described herein be limited only by the claims and theequivalents thereof.

What is claimed is:
 1. An apparatus comprising: transceiver moduleconfigured to communicate via a plurality of serving cells, wherein atleast two of the serving cells have different time division duplexing(TDD) uplink-downlink (UL-DL) configurations; and a feedback controllercoupled with the transceiver module and configured to: obtain a downlinkassignment index (DAI); determine a number of downlink subframes withina bundling window of a first serving cell of the plurality of servingcells, wherein the downlink subframes of the bundling window areassociated with an uplink subframe for transmission of correspondinghybrid automatic repeat request-acknowledgment (HARQ-ACK) information;determine a number of HARQ-ACK bits, which corresponds to the firstserving cell, available on a physical uplink shared channel (PUSCH) ofthe uplink subframe based on the DAI and the determined number ofdownlink subframes; determine a value that corresponds to the DAI;select whichever of the determined value or the determined number ofdownlink subframes is smaller as the number of HARQ-ACK bits for thefirst serving cell; and determine a HARQ-ACK codebook size on the PUSCHof the uplink subframe based on the number of HARQ-ACK bits for thefirst serving cell.
 2. The apparatus of claim 1, wherein the DAIcorresponds to a maximum value of number of scheduled downlink subframeswithin bundling windows of the plurality of serving cells, wherein thedownlink subframes within the bundling windows of the plurality ofserving cells are associated with the uplink subframe, and the feedbackcontroller is further configured to: determine the HARQ-ACK bits basedon the maximum value.
 3. The apparatus of claim 1, wherein the DAI isincluded in downlink control information (DCI) that allocates uplinktransmission resource of a serving cell having the uplink subframe. 4.The apparatus of claim 3, wherein the DCI has a format that is DCIformat 0 or DCI format
 4. 5. The apparatus of claim 1, wherein at leastone of the subframes within the bundling window include a physicaldownlink shared channel (PDSCH) transmission associated with a downlinkcontrol information (DCI) message of a physical downlink control channel(PDCCH) or a PDCCH transmission indicating downlink semi-persistentscheduling (SPS) release to a user equipment (UE) to which the HARQ-ACKinformation corresponds.
 6. The apparatus of claim 1, wherein the numberof downlink subframes within the bundling window associated with theuplink subframe does not include a special subframe of configurations 0and 5 with normal downlink cyclic prefix (CP) or of configurations 0 and4 with extended downlink CP.
 7. The apparatus of claim 1, wherein thefeedback controller is further configured to: determine a number ofHARQ-ACK bits, which correspond to each of the plurality of servingcells, available on the PUSCH of the uplink subframe; and determine aHARQ-ACK codebook size on the PUSCH of the uplink subframe based on thedetermined number of HARQ-ACK bits that correspond to each of theplurality of serving cells.
 8. The apparatus of claim 7, wherein thefeedback controller is configured to determine the HARQ-ACK codebooksize by being configured to aggregate the determined number of HARQ-ACKbits that correspond to each of the plurality of serving cells.
 9. Theapparatus of claim 1, wherein the feedback controller is furtherconfigured to: determine a number of transport blocks supported persubframe for a transmission mode of the first serving cell; anddetermine the number of HARQ-ACK bits for the first serving cell basedon the determined number of transport blocks supported per subframe. 10.The apparatus of claim 1, wherein the feedback controller is furtherconfigured to: determine a number of HARQ-ACK bits that correspond toeach serving cell of the plurality of serving cells; and determine theHARQ-ACK codebook size based on the determined number of HARQ-ACK bitsthat correspond to each serving cell of the plurality of serving cells.11. The apparatus of claim 10, wherein the feedback controller isfurther configured to determine the number of HARQ-ACK bits thatcorrespond to each serving cell of the plurality of serving cells basedon:O _(c)=min(M _(c) ^(DL) ,W _(DAI) ^(UL))*C _(c) ^(DL), where c is aserving cell index, O_(c) is the number of HARQ-ACK bits that correspondto the c^(th) serving cell, M_(c) ^(DL) is the number of downlinksubframes of a bundling window of the c^(th) serving cell, wherein thebundling window is determined according to a HARQ timing referenceconfiguration of the c^(th) serving cell and excludes special subframesof configurations 0 and 5 with normal downlink cyclic prefix (CP) and ofconfigurations 0 and 4 with extended downlink CP, W_(DAI) ^(UL) is thedetermined value that corresponds to the DAI in downlink controlinformation (DCI) format for uplink resource allocation for theplurality of serving cells, and C_(c) ^(DL) is a number of transportblocks supported per subframe for a transmission mode of the c^(th)serving cell.
 12. The apparatus of claim 1, wherein the feedbackcontroller is further configured to: determine a number of PDSCHtransmissions and PDCCH transmissions that indicate downlinksemi-persistent scheduling (SPS) release that are received in subframesof bundling windows of each of the plurality of serving cells; determinea maximum of the determined numbers of PDSCH transmissions and PDCCHtransmissions that indicate downlink SPS release that are received insubframes of bundling windows of each of the plurality of serving cells;and determine the number of HARQ-ACK bits based on the determinedmaximum.
 13. The apparatus of claim 12, wherein the feedback controlleris further configured to determine the number of HARQ-ACK bits thatcorrespond to each serving cell based on:${O_{c} = {{\min\left( {M_{c}^{DL},{W_{DAI}^{UL} + {4\left\lceil \frac{U - W_{DAI}^{UL}}{4} \right\rceil}}} \right)}*C_{c}^{DL}}},$where c is a serving cell index, O_(c) is the number of HARQ-ACK bitsthat correspond to the C^(th) serving cell, M_(c) ^(DL) is the number ofdownlink subframes in bundling window of the C^(th) serving cell,wherein the bundling window is determined according to a HARQ timingreference configuration of the C^(th) serving cell and excludes specialsubframes of configurations 0 and 5 with normal downlink cyclic prefix(CP) and of configurations 0 and 4 with extended downlink CP, W_(DAI)^(UL) is the value that corresponds to the DAI, U is the determinedmaximum, and C_(c) ^(DL) is a number of transport block supported persubframe for the transmission mode of the C^(th) serving cell.
 14. Theapparatus of claim 13, wherein the feedback controller is furtherconfigured to determine a HARQ-ACK codebook size, O, based on:${O = {\sum\limits_{c = 0}^{N_{Cells}^{DL} - 1}O_{c}}},$ where N_(Cells)^(DL) is the plurality of serving cells.
 15. The apparatus of claim 12,wherein the feedback controller is further configured to: if HARQ timingreference configuration of at least one serving cell of the plurality ofserving cells is UL-DL configuration 5, determine the number of HARQ-ACKbits that correspond to each serving cell based on:${O_{c} = {{\min\left( {M_{c}^{DL},{W_{DAI}^{UL} + {4\left\lceil \frac{U - W_{DAI}^{UL}}{4} \right\rceil}}} \right)}*C_{c}^{DL}}},$if no HARQ timing reference configurations of the plurality ofaggregated serving cells are UL-DL configuration 5, determine the numberof HARQ-ACK bits that correspond to each serving cell of the pluralityof serving cells based on:O _(c)=min(M _(c) ^(DL) ,W _(DAI) ^(UL))*C _(c) ^(DL), where c is aserving cell index, O_(c) is the number of HARQ-ACK bits that correspondto the c^(th) serving cell, M_(c) ^(DL) is the number of downlinksubframes in bundling window of the c^(th) serving cell, W_(DAI) ^(UL)is the value that corresponds to the DAI in downlink control information(DCI) format for uplink resource allocation, U is the determinedmaximum, and C_(c) ^(DL) is a number of transport blocks supported persubframe for a transmission mode of the c^(th) serving cell.
 16. Theapparatus of claim 1, wherein the uplink subframe is in a second servingcell of the plurality of serving cells.
 17. The apparatus of claim 1,wherein the number of HARQ-ACK bits corresponds to the downlinksubframes of the bundling window of the first serving cell.
 18. Theapparatus of claim 17, wherein the association of the downlink subframesof the bundling window with the uplink subframe is based on apredetermined HARQ-ACK timing reference.
 19. One or more non-transitorycomputer-readable media having instructions, stored thereon, that, whenexecuted cause a user equipment (UE) to: configure a plurality ofserving cells for communication, wherein at least two of the servingcells have different time division duplexing (TDD) uplink-downlink(UL-DL) configurations; determine a size of a bundling window forindividual serving cells of the plurality of serving cells; determine avalue that corresponds to a maximum number of scheduled downlinksubframes within the bundling windows of the plurality of serving cells;determine a size of a HARQ-ACK codebook on a first uplink subframe thatis associated with the bundling windows of the plurality of servingcells based on the size of the bundling window and the determined value;obtain a downlink assignment index; determine the value based on thedownlink assignment index; if HARQ timing reference configuration of atleast one serving cell of the plurality of serving cells isconfiguration 5, determine a number of HARQ bits for bundling windows ofthe individual serving cells based on:${O_{c} = {{\min\left( {M_{c}^{DL},{W_{DAI}^{UL} + {4\left\lceil \frac{U - W_{DAI}^{UL}}{4} \right\rceil}}} \right)}*C_{c}^{DL}}},$if no HARQ timing reference configurations of the plurality of servingcells are configuration 5, determine the number of HARQ bits forbundling windows of the individual serving cells based on:O _(c)=min(M _(c) ^(DL) ,W _(DAI) ^(UL))*C _(c) ^(DL), where c is aserving cell index O_(c) is a number of HARQ bits that correspond to thec^(th) serving cell, M_(c) ^(DL) is a number of downlink subframes inbundling window of c^(th) serving cell, wherein the bundling window isdetermined according to a HARQ timing reference configuration of thec^(th) serving cell and excludes special subframes of configurations 0and 5 with normal downlink cyclic prefix (CP) and of configurations 0and 4 with extended downlink CO, W_(DAI) ^(UL) is the determined valuefor the plurality of serving cells U_(c) is a number of physicaldownlink shared channel (PDSCH) transmissions and physical downlinkcontrol channel (PDCCH) transmissions that indicate downlinksemi-persistent scheduling (SPS) release that are received in subframesof bundling window of c^(th) serving cell U is a maximum of the U_(c) sand C_(c) ^(DL) is a number of transport blocks supported per subframefor transmission mode of the c^(th) serving cell.
 20. The one or morenon-transitory computer-readable media of claim 19, wherein theinstructions, when executed, further cause the UE to: puncture physicaluplink shared channel (PUSCH) resource elements with HARQ-ACK symbolsbased on the determined size of the HARQ-ACK codebook.
 21. One or morenon-transitory computer-readable media having instructions that, whenexecuted, cause a feedback controller to: obtain a downlink assignmentindex (DAI); and if a HARQ timing reference configuration of at leastone serving cell of a plurality of configured serving cells isconfiguration 5, determine a number of HARQ-ACK bits that correspond toeach serving cell based on:${O_{c} = {{\min\left( {M_{c}^{DL},{W_{DAI}^{UL} + {4\left\lceil \frac{U - W_{DAI}^{UL}}{4} \right\rceil}}} \right)}*C_{c}^{DL}}},$if none of the HARQ timing reference configurations of the plurality ofconfigured serving cells are configuration 5, determine the number ofHARQ-ACK bits that correspond to each serving cell of the plurality ofserving cells based on:O _(c)=min(M _(c) ^(DL) ,W _(DAI) ^(UL))*C _(c) ^(DL), where c is aserving cell index, O_(c) is a number of HARQ bits that correspond tothe c^(th) serving cell, M_(c) ^(DL) is a number of downlink subframesin bundling window of c^(th) serving cell, wherein the bundling windowis determined according to a HARQ timing reference configuration of thec^(th) serving cell and excludes special subframes of configurations 0and 5 with normal downlink cyclic prefix (CP) and of configurations 0and 4 with extended downlink CP, W_(DAI) ^(UL) is a value thatcorresponds to the DAI in downlink control information (DCI) format foruplink resource allocation, U_(c) is a number of physical downlinkshared channel (PDSCH) transmissions and physical downlink controlchannel (PDCCH) transmissions that indicate downlink semi-persistentscheduling (SPS) release that are received in subframes of bundlingwindow of c^(th) serving cell, U is a maximum of the U_(c)s, and C_(c)^(DL) is a number of transport blocks supported per subframe fortransmission mode of the c^(th) serving cell.
 22. The one or morenon-transitory computer-readable media of claim 21, wherein theinstructions, when executed, further cause the feedback controller to:determine a System Information Block 1 (SIB1) configuration for aprimary serving cell (PCell) of the plurality of serving cells;determine a SIB1 configuration for a second secondary serving cell(SCell) of the plurality of configured serving cells; and determine aHARQ timing reference configuration for the SCell based on the SIB1configuration of the PCell and the SIB1 configuration of the SCell. 23.The one or more non-transitory computer-readable media of claim 22,wherein the instructions, when executed, further cause the feedbackcontroller to: determine a number of downlink subframes in bundlingwindow of the SCell based on the determined HARQ timing referenceconfiguration.
 24. The one or more non-transitory computer-readablemedia of claim 21, wherein the instructions, when executed, furthercause the feedback controller to: determine a UL-DL configuration for aprimary serving cell (PCell) of the plurality of configured servingcells; determine a UL-DL configuration for a second secondary servingcell (SCell) of the plurality of configured serving cells; and determinea HARQ timing reference configuration for the SCell based on the UL-DLconfiguration of the PCell and the UL-DL configuration of the SCell. 25.The one or more non-transitory computer-readable media of claim 21,wherein the instructions, when executed, further cause the feedbackcontroller to: puncture physical uplink shared channel (PUSCH) resourceelements with the determined number of HARQ-ACK bits.
 26. A methodcomprising: obtaining, with feedback control circuitry, a downlinkassignment index (DAI); and if a HARQ timing reference configuration ofat least one serving cell of a plurality of configured serving cells isconfiguration 5, determining, with the feedback control circuitry, anumber of HARQ-ACK bits that correspond to each serving cell based on:${O_{c} = {{\min\left( {M_{c}^{DL},{W_{DAI}^{UL} + {4\left\lceil \frac{U - W_{DAI}^{UL}}{4} \right\rceil}}} \right)}*C_{c}^{DL}}},$if none of the HARQ timing reference configurations of the plurality ofconfigured serving cells are configuration 5, determining, with thefeedback control circuitry, the number of HARQ-ACK bits that correspondto each serving cell of the plurality of serving cells based on:O _(c)=min(M _(c) ^(DL) ,W _(DAI) ^(UL))*C _(c) ^(DL), where c is aserving cell index, O_(c) is a number of HARQ bits that correspond tothe c^(th) serving cell, M_(c) ^(DL) is a number of downlink subframesin bundling window of c^(th) serving cell, wherein the bundling windowis determined according to a HARQ timing reference configuration of thec^(th) serving cell and excludes special subframes of configurations 0and 5 with normal downlink cyclic prefix (CP) and of configurations 0and 4 with extended downlink CP, W_(DAI) ^(UL) is a value thatcorresponds to the DAI in downlink control information (DCI) format foruplink resource allocation, U_(c) is a number of physical downlinkshared channel (PDSCH) transmissions and physical downlink controlchannel (PDCCH) transmissions that indicate downlink semi-persistentscheduling (SPS) release that are received in subframes of bundlingwindow of c^(th) serving cell, U is a maximum of the U_(c)s, and C_(c)^(DL) is a number of transport blocks supported per subframe fortransmission mode of the c^(th) serving cell.
 27. The method of claim26, further comprising: determining a System Information Block 1 (SIB1)configuration for a primary serving cell (PCell) of the plurality ofserving cells; determining a SIB1 configuration for a second secondaryserving cell (SCell) of the plurality of configured serving cells; anddetermining a HARQ timing reference configuration for the SCell based onthe SIB1 configuration of the PCell and the SIB1 configuration of theSCell.
 28. The method of claim 27, further comprising: determine anumber of downlink subframes in bundling window of the SCell based onthe determined HARQ timing reference configuration.
 29. The method ofclaim 26, further comprising: determining a UL-DL configuration for aprimary serving cell (PCell) of the plurality of configured servingcells; determining a UL-DL configuration for a second secondary servingcell (SCell) of the plurality of configured serving cells; anddetermining a HARQ timing reference configuration for the SCell based onthe UL-DL configuration of the PCell and the UL-DL configuration of theSCell.
 30. The method of claim 26, further comprising: puncturingphysical uplink shared channel (PUSCH) resource elements with thedetermined number of HARQ-ACK bits.